Hi,

I have a 13B turbo engine that I’m planning to use on my Vision but
without the turbo. Attached is a circuit for a CDI electronic ignition
system that I’m planning to build for my plane. The “distributor” on my
engine, have two reluctor pickups. One with a 24 tooth disc and one with
a two tooth disc.

My questions are as follow,

   1. What do they sense with the 24 tooth disc?
   2. If I build two of the CDI’s, can I replace the 24 tooth disc with
      another 2 tooth disc and with that have two independent ignition
      systems, each one with it’s own reluctor pickup?
   3. Or am I missing something?
   4. Can you perhaps supply me with full size etching pattern for the
      PC board of your TLC 555 driven Electronic Fuel Injection?

Thanks for all the info that you supply on the Rotary Forum.

Regards,

Pierre Swanepoel

South Africa


Exactly!!!! :)

It is near impossible to say what is going on in the computer as Mazda does
not publish the software source code. That is precisely my objection to 99.9% of computer
controlled fuel and ignition systems. You are kept in the dark and fed fertilizer. Just like
a mushroom. The 555 systems do not need or use software.

Yes I have that right here.

In a 555 system you need two sensors 180 degrees apart to trigger the fuel injection.
Two more for simple ignition and only one tooth on a steel wheel. The angular positions
of the sensors control when the injectors are fired and
when the spark plugs are fired. Simple!!! Move the sensors to change the angles and hence
the timing. Fixed timing works fine for aircraft engines. Magneto  timing is fixed
at about 22 degrees BTDC.

Paul Lamar